From 3e03989b5868acf69a391a424dc71fcd6cc48167 Mon Sep 17 00:00:00 2001
From: Roland Dreier <roland@purestorage.com>
Date: Wed, 31 Oct 2012 09:16:45 -0700
Subject: [PATCH] target: Avoid integer overflow in se_dev_align_max_sectors()
The expression (max_sectors * block_size) might overflow a u32
(indeed, since iblock sets max_hw_sectors to UINT_MAX, it is
guaranteed to overflow and end up with a much-too-small result in many
common cases). Fix this by doing an equivalent calculation that
doesn't require multiplication.
While we're touching this code, avoid splitting a printk format across
two lines and use pr_info(...) instead of printk(KERN_INFO ...).
Signed-off-by: Roland Dreier <roland@purestorage.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
drivers/target/target_core_device.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 8d774da163207..9abef9f8eb760 100644
--- a/drivers/target/target_core_device.c
+++ b/drivers/target/target_core_device.c
@@ -850,20 +850,20 @@ int se_dev_check_shutdown(struct se_device *dev)
static u32 se_dev_align_max_sectors(u32 max_sectors, u32 block_size)
{
- u32 tmp, aligned_max_sectors;
+ u32 aligned_max_sectors;
+ u32 alignment;
/*
* Limit max_sectors to a PAGE_SIZE aligned value for modern
* transport_allocate_data_tasks() operation.
*/
- tmp = rounddown((max_sectors * block_size), PAGE_SIZE);
- aligned_max_sectors = (tmp / block_size);
- if (max_sectors != aligned_max_sectors) {
- printk(KERN_INFO "Rounding down aligned max_sectors from %u"
- " to %u\n", max_sectors, aligned_max_sectors);
- return aligned_max_sectors;
- }
+ alignment = max(1ul, PAGE_SIZE / block_size);
+ aligned_max_sectors = rounddown(max_sectors, alignment);
+
+ if (max_sectors != aligned_max_sectors)
+ pr_info("Rounding down aligned max_sectors from %u to %u\n",
+ max_sectors, aligned_max_sectors);
- return max_sectors;
+ return aligned_max_sectors;
}
void se_dev_set_default_attribs(
--
2.30.2